AI Diagnostics

Can AI Detect Impacted Teeth on OPG? Impaction, Angulation & Nerve Proximity, Explained

One panoramic film, three separate clinical questions before you book an extraction: is the tooth impacted, which way is it angled, and how close does the root actually sit to the nerve. AI answers each with a different confidence level — here's what the published data says about all three.

8 min readUpdated July 2026Clinical Reviewer: Dr. Chandravir Singh

What this article covers

How accurately AI detects impacted third molars on a standard OPG, how well it classifies angulation using Winter's and Pell & Gregory systems, what the data shows on AI's ability to flag proximity to the inferior alveolar nerve — and why that last one still deserves a CBCT before anyone picks up a handpiece.

Why third molar workup is where AI gets tested hardest

Third molar extraction is, by most counts, the single most common procedure an oral surgeon performs. It's also one of the few dental procedures where the pre-op read genuinely changes the treatment plan — not just the diagnosis. A mesioangular impaction sitting clear of the canal is a routine chairside extraction. The same tooth horizontally impacted with its root crossing the inferior alveolar canal is a referral, a CBCT, and a very different conversation with the patient about nerve injury risk.

That's three separate reads stacked into one film:

  • Detection — is there an impacted tooth here at all, and where
  • Angulation — which way is it tilted (Winter's classification), and how deep (Pell & Gregory)
  • Nerve proximity — does the root sit close enough to the inferior alveolar canal to change the surgical approach

Each of those three has a different amount of published evidence behind it. Lumping them into one “can AI read a wisdom tooth X-ray” question is where most of the confusion — and most of the marketing overreach — comes from.

Well-Validated Today

  • Detecting an impacted tooth on OPG
  • Classifying angulation (Winter's, Pell & Gregory)
  • Flagging cases for closer surgical review

Genuinely Harder

  • True root-to-nerve contact on a 2D film
  • Bone canal wall continuity around the root
  • Distinguishing overlap from actual proximity

Where AI Helps Most

  • Pre-sorting routine vs. surgically complex cases
  • Deciding who needs a CBCT before they're booked
  • A second, consistent read on every OPG, every time
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Two classification systems, doing two different jobs

Winter's classification describes the angle of the impacted tooth relative to the second molar — mesioangular, distoangular, vertical, horizontal. Pell & Gregory describes depth and available space (Class I–III, position A–C). Surgeons use both together to gauge difficulty before they touch a handpiece, and it's exactly this combination that recent detection models have been trained to reproduce.

What the accuracy data actually shows

Start with detection, because it's the strongest number on this page. A 2025 model built on VGG16 for detection and ResNet50 for classification — trained and tested on 1,100 panoramic radiographs containing 1,200 impacted mandibular third molars — hit 93.51% detection accuracy. Not a lab curiosity. An oral radiologist validated every annotation first.

93.5%

Detection accuracy

Impacted mandibular third molars, OPG

J. Oral Med. Oral Surg., 2025

0.98

mAP@50, angulation classification

Winter's + Pell & Gregory, YOLOv11

Scientific Reports, 2025

72.3% vs 52.7–69.6%

True nerve-contact accuracy

AI vs. six OMFS specialists

Scientific Reports, 2023

That third card is the one worth actually reading twice. Six oral and maxillofacial surgery specialists — not students, not general dentists — were asked to determine true root-to-canal contact from a panoramic film alone. Their accuracy ranged from 52.68% to 69.64% — a coin flip would get you most of the way to the bottom of that range. The AI model, trained against CBCT-verified ground truth, came in at 72.32% — and on a related sub-task, judging bucco-lingual position of the nerve relative to the root, the gap widened further: AI at 80.65% against a specialist range of just 32.26% to 48.39%.

  • Contact determination: AI 72.3% vs. OMFS specialist range 52.7%–69.6% — a genuinely hard 2D read where trained eyes struggle
  • Bucco-lingual positioning: AI 80.65% vs. specialist range 32.3%–48.4% — the widest gap on this list
  • Cohen's kappa for AI: 0.61 (substantial agreement) vs. poor inter-rater agreement among the specialist panel on the same task
  • Translation: this isn't AI landing between two humans the way lesion detection often does — on nerve positioning specifically, panoramic radiographs are just a hard 2D read for anyone, and the model's advantage comes from being trained against a 3D reference the human eye never had

Three reads, three very different accuracy ceilings

How to read this

Detection

Is a tooth impacted, and where? Mature, well-studied, over 93% accuracy across multiple architectures.

Angulation

Winter's / Pell & Gregory classification. Also strong — precision above 0.95 in recent object-detection models.

Nerve proximity

Contact and bucco-lingual position. Improving fast, beats unaided human reads on OPG, but still a screening signal — not a surgical verdict.

Why nerve proximity is the hardest of the three — for humans and AI alike

A panoramic radiograph flattens a three-dimensional jaw into a two-dimensional strip. Somewhere in that flattening, the actual spatial gap between a root tip and the inferior alveolar canal gets lost — a root can appear to overlap the canal on film while sitting a full millimeter buccal or lingual to it in real anatomy. That's not a training-data gap AI can simply be fed more of. It's a physical limitation of the imaging modality itself.

Which is exactly why the numbers above matter. AI isn't overcoming that limitation — nobody has. What it's doing is reading the same ambiguous 2D signal more consistently than a tired surgeon on their eleventh OPG of the day, and doing it against a CBCT-anchored ground truth most human readers never get to calibrate against in daily practice.

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Dentist plus AI still beats either one alone

One study measured average precision on nerve-relationship detection three ways: dentists working alone (76.45%), an AI model working alone (83.02%), and dentists using the AI as a second opinion (88.06%). The pattern shows up everywhere this gets tested rigorously — assisted humans outperform either the unaided clinician or standalone AI. Nobody comes out ahead by removing the other from the workflow.

Where it still falls short

"Ground truth" itself is contested. Different studies verify true nerve contact against different references — some against CBCT, some against surgical findings, some against senior-radiologist consensus. Accuracy numbers across studies (52% to 89%+) aren't always measuring the exact same thing, which is worth remembering before treating any single figure as gospel.

Canal wall continuity is a weaker read than contact alone. One 2022 model that scored 0.860 accuracy on contact detection dropped to 0.766 on the more surgically relevant question of whether the canal's cortical wall stayed intact — a meaningfully harder sub-task that current models haven't fully cracked.

A "low risk" flag on OPG isn't a green light. Standard surgical protocol routes panoramic radiographs showing classic radiographic signs of proximity — darkening of the root, interruption of the canal's white line, deflection of the root — into CBCT confirmation before finalizing a surgical plan. AI screening doesn't change that referral pathway; it changes how fast you get to the decision to refer.

Angulation classification is mature; the nerve question isn't there yet. Don't let a strong 98% mAP on Winter's classification create false confidence about a 72–89% accuracy range on a much harder, much higher-stakes anatomical question.

No AI output carries surgical sign-off. The oral surgeon's license and clinical judgment — not a confidence score — is what stands behind the decision to extract, refer, or scan further.

TaskAI on OPGClinician on OPG aloneWhere the difference comes from
Detecting the impacted toothStrong (93.5%)StrongMature, well-represented task for both
Angulation classificationStrong (0.98 mAP)StrongDeterministic geometry, easy to label and train on
True nerve contactModerate (72–89%)Weak (53–70%)2D projection loses real depth; AI trained on CBCT-anchored data
Canal wall continuityEarly-stage (~77%)Not reliably testedSubtler radiographic sign, less training data available
Decision to extract or refer for CBCTNot applicableStrongClinical judgment and licensure, not pattern recognition

What this means for your practice

  • Douse AI to triage every incoming OPG — flag impaction, angulation, and nerve-proximity risk automatically so you know which patients need a CBCT booked before they're back in the chair a second time
  • Don'ttreat a low-risk AI flag as clearance to skip CBCT on a case that shows classic radiographic proximity signs — the screening call and the surgical decision are two different things

Medecro's AI X-Ray Analyzer runs exactly this triage on OPG and RVG — impaction detection, angulation classification, and a proximity-to-IAN risk flag, with confidence scores and one-click override, inside the workflow you already use. It's built to speed up which third molars need a closer look, not to replace the CBCT or the surgeon's final call on the ones that do.

Medecro AI X-Ray Analyzer

Flag impaction, angulation, and nerve proximity on every OPG — before the patient sits down twice

Confidence-scored detection built for third molar workup, with one-click override, inside your existing clinic workflow. It sorts which cases need a closer look — it doesn't replace the CBCT or the surgeon's call on them.

Book a Demo — See It Live

Frequently asked questions

Yes — this is one of the more mature applications on this page. Recent object-detection models trained on Winter's classification report precision above 0.95 and mAP@50 around 0.98 when tested against radiologist-labeled panoramic datasets.

Impacted Third MolarAI RadiologyWinter's ClassificationInferior Alveolar NerveExtraction PlanningOPG AnalysisDental AI

Sources & references

  • Veerabhadrappa S.K. et al. Fully Automated Deep Learning Framework for Detection and Classification of Impacted Mandibular Third Molars in Panoramic Radiographs.Journal of Oral Medicine and Oral Surgery, 2025.
  • Deep Learning-Based Approach to Third Molar Impaction Analysis with Clinical Classifications.Scientific Reports, 2025.
  • Automatic Diagnosis of True Proximity Between the Mandibular Canal and the Third Molar on Panoramic Radiographs Using Deep Learning.Scientific Reports, 2023.
  • Artificial Intelligence in Positioning Between Mandibular Third Molar and Inferior Alveolar Nerve on Panoramic Radiography.Scientific Reports, 2022.
  • Deep Learning Model for Analyzing the Relationship Between Mandibular Third Molar and Inferior Alveolar Nerve in Panoramic Radiography.Scientific Reports, 2022.
  • Fully Automated Deep Learning Model for Detecting Proximity of Mandibular Third Molar Root to Inferior Alveolar Canal Using Panoramic Radiographs.PubMed, 2024.
  • Artificial Intelligence Model to Detect Real Contact Relationship Between Mandibular Third Molars and Inferior Alveolar Nerve Based on Panoramic Radiographs.PMC, 2021.
  • Application of Deep Learning in Evaluating the Anatomical Relationship Between the Mandibular Third Molar and Inferior Alveolar Nerve: A Scoping Review.PMC, 2025.